A conventional boat trailer utilizes an axle secured to a trailer frame to support a wheel. The wheel is coupled to the axle by use of a wheel hub assembly. The wheel hub assembly employs inner and outer bearings with an associated inner and outer race, which permits rotational movement in relation to the axle. Proper lubrication of the bearings is critical in controlling heat and premature bearing wear. Larger trailers require a braking system, which can further add to the heat buildup.
Torsion axles are now commonly used on light weight trailers, wherein a spindle axle is welded into a torsion arm. The torsion arm is further welded to a square bar that is seated inside a square shaped axle beam. The four inside corners of the square axle beam accept rubber cords that provide resistance to the rotation of the torsion bar, yet provide unique cushioning to provide a softer ride.
Problems with the axles and the wheel assemblies are pronounced when the trailers are used to transfer boats, especially those used in salt water. For instance, a boat trailer may have been pulled for a long period of time, causing the axle and wheel assembly to heat up. The boat trailer may be placed in the water before the metals have cooled, such as when unloading the boat. The heat build-up during normal operation of the trailer (i.e. bearing rotation and brake application) can result in very high axle and wheel assembly temperatures wherein no conventional corrosion inhibitor will provide adequate protection.
While axle assemblies, wheel assemblies, and brake assemblies could be constructed from high quality materials to lessen corrosion, the costs make it prohibitively expensive for the consumer. Further, even if an assembly is constructed from high quality materials, ions from dissimilar materials will tend to leach, leading to galvanic corrosion, especially when the materials are subjected to salt water.
U.S. Pat. No. 6,299,259 discloses a removable spindle axle for torsion axle assembly. In this disclosure, a torsion axle assembly has removable and replaceable spindle axles. The assembly comprises a tubular axle beam, an inner torsion bar seated inside the tubular axle beam, rubber cords positioned in the four corners of the tubular axle beam for providing resistance to the inner torsion bar, torsion arms rigidly secured to the inner torsion bar at opposing ends thereof, and removable spindle axles. A removable spindle axle generally includes a body of defined taper arranged and configured to be mounted in abutment with the spindle axle socket of the torsion arms, a threaded fastener for securing the spindle axle to the torsion arm, and a spindle end that is arranged and configured to mount a wheel and hub assembly thereon. A damaged spindle can be the result of many different circumstances, but commonly is the result of wheel bearing damage.
While the concept was to provide a readily removable and replaceable spindle, in reality, the spindle becomes nearly impossible to remove without great effort. The problem is a result of corrosion involving the threaded fastener; also known as a castle nut. The threaded fastener is typically used with a flat beveled washer and a cotter pin to prevent removal. It is impractical to match all the materials used in manufacturing, or employ materials having no iron content, making galvanic action. Most cost effective stainless steels include iron, which will begin to oxidize when exposed to an electrolyte, water being a known electrolyte. While water enables oxidation, salt water is a very good conductor; therefore, galvanic corrosion reactions are tremendously accelerated by salt water. Metal atoms can react with other elements, becoming charged. Once charged, they are attracted to water molecules and dissolve. For this reason, it is common for the threaded fastener, washer and cotter pin to become so corroded they have to be cut off from a stainless steel spindle.
U.S. Publication No. 2017/0297404 discloses a removable spindle assembly for torsion axles. In this disclosure, a torsion axle arrangement is provided, wherein the spindle is mounted to the suspension link by insertion into a split socket at one end of the suspension link, which is inclined with respect to the longitudinal axis of the suspension link. That connection is maintained by a bolt passing through the suspension link, engaging a mating groove in the spindle, and then clamping the ends of the split socket together. The bolt is anchored to the suspension link by a threaded connection external to the suspension link. A chamfer or surface recess is formed in the surface of the suspension link for immediate source identification.
U.S. Publication 2015/0145229 discloses a removable spindle assembly for torsion axles. In this disclosure, a torsion axle arrangement is provided, wherein the spindle is mounted to the suspension link by a keyed connection facilitated with a selectively orientable disc, then fixed to the suspension link according to a given application. That connection is maintained by a bolt passing through the suspension link and engaging a mating groove in the spindle. The bolt is anchored within the suspension link by a threaded connection internal to the suspension link. The shape of the key can be selected as desired for immediate source identification.
U.S. Pat. No. 7,234,783 discloses an axle with removable spindle and cam key. In this disclosure, the axle assembly includes a spindle that extends through a mounting collar into the open end of the axle. A cam key moves through a key hole in the axle and registers with the cam slot of the spindle. The cam surface of the cam key is reversible, with the cam surface engaging either the bearing surface or the bearing surface of the spindle, to urge the spindle into or out of the axle.
What is needed in the industry is a sealing mechanism for a torsion axle assembly so as to maintain the ability to remove a spindle during the life of the assembly.